Functional Groups and Their Characteristics

• Hydroxyl:

  • Polar, forms hydrogen bonds.
  • Present in: sugars, some amino acids, alcohols.

• Carbonyl:

  • Polar.
  • Present in: sugars.

• Carboxyl:

  • Polar, acidic.
  • Present in: fatty acids, amino acids.

• Amino:

  • Polar, basic.
  • Forms hydrogen bonds.
  • Present in: amino acids.

• Sulfhydryl:

  • Polar.
  • Forms disulfide bonds.
  • Present in: some amino acids.

• Phosphate:

  • Polar, acidic.
  • Present in: nucleotides, phospholipids.

Isomers

• Definition: Organic molecules with the same molecular formula but different atom arrangements.
  • Example: Butane vs. Isobutane (C4H10).

Monomers, Polymers, and Macromolecules

• Monomer:

  • Simple molecules; building blocks of polymers.
  • Examples: monosaccharides, amino acids, nucleotides.

• Polymer:

  • Large molecules formed from many monomers.
  • Examples: polysaccharides, proteins, nucleic acids.

• Macromolecule:

  • Large biological molecules (proteins, polysaccharides, nucleic acids).

Hydrolysis and Condensation Reactions

• Condensation/Dehydration synthesis:

  • Monomers link by removing water (hydroxyl and hydrogen).
  • Water is released when bonds are formed.

• Hydrolysis:

  • Water is added to break down polymers into monomers.
  • Hydroxyl group adds to one monomer and hydrogen to another.

Carbohydrates

Types of glucose

• Alpha and beta glucose:
  • Isomers differing by the position of the hydroxyl (OH) group on carbon 1.
  • Alpha (α): OH below the ring.
  • Beta (β): OH above the ring.

Energy Storage

• Starch:

  • Short-term energy storage in plants (found in chloroplasts).
  • Contains amylose (unbranched, α 1,4 bonds) and amylopectin (branched, α 1,4 and α 1,6 bonds).

• Glycogen:

  • Short-term energy storage in liver/muscles (more branched than amylopectin).
  • Branching via α 1,6 glycosidic bonds.

Structural Polysaccharides

• Cellulose:

  • Polymer of beta glucose, forms β 1,4 glycosidic bonds.
  • Hydrogen bonds create microfibrils, providing structural support in plants.

• Chitin:

  • Similar to cellulose with amino groups, found in fungi cell walls and arthropod exoskeletons.

Lipids

Types of Lipids

• Triglycerides:

  • Composed of glycerol and three fatty acids (ester bonds).
  • Fats (saturated) are solid, oils (unsaturated) are liquid at room temp.

• Phospholipids:

  • Two fatty acids and a phosphate group, main component of cell membranes.

• Steroids:

  • Includes cholesterol and hormones (e.g., estrogen, testosterone).

• Waxes:

  • Prevent water loss, found in plant cuticles.

Fatty Acid Types

• Saturated fatty acids: No double bonds, solid at room temperature.
• Unsaturated fatty acids: At least one double bond, liquid at room temperature.

Proteins

• Polymers of amino acids:

  • Each amino acid has an amino group, carboxyl group, and an R group (determines properties).

• Levels of protein structure:

  1. Primary Structure: Linear sequence of amino acids (determined by genes).
  2. Secondary Structure: Folding into alpha helices and beta sheets (hydrogen bonds).
  3. Tertiary Structure: 3D shape (bonds: covalent, ionic, hydrogen, hydrophobic interactions, disulfide bonds).
  4. Quaternary Structure: Multiple polypeptide chains (e.g., hemoglobin).

• Denaturation: Loss of 3D shape due to extreme conditions (pH, temperature).

Nucleic Acids

• Polymers of nucleotides:

  • Each nucleotide has a nitrogenous base, a pentose sugar, and a phosphate group.
  • Purines: Adenine (A), Guanine (G). Pyrimidines: Cytosine (C), Thymine (T), Uracil (U).

• DNA vs. RNA:

  • DNA: double-stranded, deoxyribose, base pairing A-T, C-G.
  • RNA: single-stranded, ribose, base pairing A-U, C-G.

• ATP:

  • Energy currency of the cell, comprises adenine, ribose, and three phosphate groups.
  • ATP hydrolysis releases energy from bonds between phosphates.

Additional Concepts

• Importance of gene mutations on protein structure and function.
• Stability variations in proteins affected by R-group interactions.